Optical fibers and components to manipulate optical signals are becoming pervasive elements of modern telecommunications networks.
An optical fiber confines light signals within a narrow inner core that allows the light signals to propagate long distances within the fiber. A single-mode fiber, for example, typically has an inner core diameter on the order of eight microns. At some point, such optical signals exit the fiber for downstream processing. Thus, the light signals are xe2x80x9ccoupledxe2x80x9d from the optical fiber to subsequent optical components, e.g., lenses, switches, detectors, mirror arrays, amplifiers, etc. Similarly, light signals are coupled into optical fibers from similar such components as well as sources. To facilitate such coupling, focusing elements such as a lens (e.g., a gradient index lens or ball lens) can be positioned relative to the optical fiber to collimate light emerging from, or focus light into, the narrow fiber core. Optimizing the efficiency of such coupling typically require precise positioning and alignment of the respective optical components. This is true not only of optical fibers and coupling lenses, but optical components in general.
In general, in one aspect, the invention features a method for attaching a surface of a first optical element to a surface of a second optical element. The method includes: providing a bonding glass on at least one of the surfaces, wherein the bonding glass is selected to match the refractive indices of the first and second optical elements at the surfaces over a first range of wavelengths and absorb optical energy to a greater extent than that of the optical elements over a second range of wavelengths different from the first range of wavelengths; positioning the surfaces proximate one another; directing optical energy to the bonding glass through at least one of the optical elements at a wavelength in the second range of wavelengths, wherein the optical energy is sufficient to melt the bonding glass without deforming the optical elements; and allowing the melted bonding glass to solidify and fuse the proximately positioned surfaces.
In general, in another aspect, the invention features an optical assembly including: a first optical component having a first surface; a second optical component having a second surface; and a bonding glass fusing the first surface to the second surface, wherein the bonding glass is selected to match the refractive indices of the first and second optical elements at the surfaces over a first range of wavelengths, and wherein the bonding glass is selected to absorb optical energy to a greater extent than that of the optical elements over a second range of wavelengths different from the first range of wavelengths such that optical energy directed to the bonding glass through at least one of the optical elements at a wavelength in the second range of wavelengths can melt the bonding glass without deforming the optical elements.
Other aspects, features, and advantages of the invention will be apparent from the following detailed description and from the claims.